Solenoid-actuated valves are widely used in the mechanical arts for a wide variety of applications. For example, solenoid-actuated valves are used in refrigerant circuits, electro-hydraulic braking systems, evaporative control systems, and in compressed air systems. Solenoid-actuated valves provide a mechanism for electronically controlling the flow of a fluid in various hydraulic and pneumatic systems.
In a conventional solenoid-actuated valve, a movable armature is slidably disposed in a chamber that is surrounded in the longitudinal direction by a coil that can be energized to produce a desired magnetic field within the chamber. A magnetic pole piece is provided at one end of the chamber and a spring, such as a coil spring, is disposed against the armature, providing a biasing force urging the armature away from the pole piece. The pole piece and the armature are made substantially from ferrous material(s), and are positioned in the chamber such that when the coil is energized, the magnetic field will tend to urge the armature toward the pole piece, against the elastic force of the spring. In the desired operation, therefore, when the coil is not energized, the slideable armature is urged toward a first position away from the pole piece, and when the coil is energized, the armature is urged toward a second position, toward the pole piece. Such movement of the armature may be utilized so as to open and close the valve.